JavaScript Code Compressors
Packer
This JavaScript compressor/obfuscator by Dean Edwards is used to compress the jQuery source code. It’s available as a web-based tool or as a free download. The resulting code is very efficient in file size, at a cost of a small increase in execution time:
http://dean.edwards.name/packer/
http://dean.edwards.name/download/#packer
JSMin
Created by Douglas Crockford, JSMin is a filter that removes comments and unnecessary white space from JavaScript files. It typically reduces file size by half, resulting in faster downloads:
http://www.crockford.com/javascript/jsmin.html
Pretty Printer
This tool prettifies JavaScript that has been compressed, restoring line breaks and indentation where possible. It provides a number of options for tailoring the results:
http://www.prettyprinter.de/